I'm very pleased to learn that I've gotten a few new readers to the blog recently, so I thought this would be a good opportunity to revisit some of the things that I take for granted when I'm doing a project like this, but wasn't told early enough for me to save myself some trouble. So along the way, I'll be throwing in a few hobbyist tips.
For example, the first thing I do when I walk into my workshop/garage, is put on a pair of latex gloves. You can get 100 of them for about five bucks at home depot, and let me tell you, they are life savers. I don't wear them for my health, by the way, though I'm sure it's of benefit not to be handling all kinds of chemicals and solvents directly. I wear them simply because I don't want to spent five hours scrubbing my hands and under my fingernails after each session in the garage. That's one lesson I learned the hard way in my early days of slinging resin.
Here's the big belt in its matrix that I poured up last night. Oh, I forgot. So a matrix is not only a structure used in linear algebra and other kinds of math, but in this context, think of it as a rigid cradle for something flexible. That's what a matrix is. Oh, I think they also made a movie or two using that word in the title. Always makes you sound pretty sophisticated when you use it in casual conversation. I highly recommend it.
And here's how it looks now that it's all cured.
First order of business is to take a look at the small mold. Here's how it looks right after I pulled the foil off the back:
Pretty darn good, though there is some excess resin bleeding into the area of the mold I want to pour up, so I'm going to clean that out. I used a rubber mallet and a flat head screwdriver to gently chisel the stuff out.
I assume everyone has a jar of vaseline and a chip brush lying around. Right?? Well, it's time to make good use of them. The bummer/advantage of most resins is that they adhere to themselves to some degree. So if you pour wet resin over dry resin, there's a good chance it will stick. The way I poured up my matrices (That's the proper plural of Matrix, by the way. Not "Matrixes". That's a fake word) is such that there's a couple tiny points where there could be some resin-on-resin contact. So I'm going to slather vaseline over those parts to make sure that they will not stick, just in case there's some contact. For good measure, I'll slather some all around the edges too, just in case I get sloppy.
There was a corner of the mold that proved a little too deep to fill with a slathering of resin, so I just jammed some clay in there. That should do nicely.
Next up is the baby powder. This is KEY to running resin in ANY RTV mold. Oh, RTV stands for Room Temperature Vulcanization, and basically means a two part silicone rubber. The baby powder uses capilary action to draw resin into the tiny nooks and crannies of your molds. Your positives will come out 100 times better if you powder your molds before pouring anything into them.
I usually just splash baby powder around the inside of the mold, brush it around with a chip brush, then blow it out.
With the mold all prepped, I levelled it by using little clumps of clay around the corners. Clay allows me to maneuver the mold to perfect flatness during the pouring process. I sometimes use a stack of popsicle sticks under an offending, low hanging corner, but I chose to use clay this time.
With the mold all prepped, it's time to pour it up.
For some reason, it was only very recently that I realized how easy it is to pour out equal amounts of a substance when you're going into clear cups. I usually use the typical red cups, and they've served me well for years. I like them for smaller amounts of resin, because there are ridges on the cups that you can use as indicators.
A reminder about 1630: it is NOT a good choice for casting up resin parts that will see action. It's actually designed for reproducing molds, but makes for a great gel coat, and is optimal (in my opinion) for making masters.
For extra credit, the bold reader can check out this data sheet on 1630 for more information. I order most of my stuff from Burman Industries, up in the valley. Great people, and they've been supplying stuff to hobbyists and the industry for as long as I've been playing with this stuff.
I started my pour into the mold, and this is where some real artistry comes in. I pour slowly, so I can see the way the resin is flowing. That allows me to detect if the mold is not lying flat. I can add more clay under one corner, or push down on another if that is the case. As you can see from the inital pour, it's actually pretty good.
With the mold confirmed as lying flat, I finish up the pour, and bring the resin up the very edge of the mold. It bulges over a bit, but that's how I want it.
Now I just repeat the process on the large mold. I'll skip the first few steps, and go straight to the different parts.
I may be going overboard on the large one, but I wanted to make REALLY sure that the belt was sitting level, so I pulled out my level. Checked it on the X and Z axis to make sure it was totally laying flat.
Then I just repeated the mixing and pouring process, and it was all done.
And here is the finished product. Well, finished for now. Because 1630 needs 24 hours to fully cure (another GREAT reason NOT to use it as a traditional casting resin) I still have to demold tomorrow. But I'm very happy with today's results.
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